New classes of superconducting materials which take the form of ceramics, or mixed metal oxides, have been recently discovered, many of which exhibit superconductivity above the temperature of liquid nitrogen, 77.degree.K, at ambient pressure. The discovery of these materials signifies the ability to prepare and maintain superconductive materials now in virtually any laboratory. These mixed metal oxides are typically made by sputtering appropriate metals and/or metal oxides onto a substrate and sintering to form the requisite ceramic structure. Another method involves coprecipitating the appropriate metals from aqueous solutions of their nitrate salts, then heating the precipitate at 900.degree. C. to 950.degree. C. to form the appropriate ceramic structure.
One of the problems, however, with these ceramic materials is that they are brittle, hard and difficult to handle without damaging the ceramic. This means that the mixed metal oxides are particularly difficult to form into wire or fiber, which might be useful for high-current applications. For small scale applications, such as for components in microcircuitry, the low current-carrying capacity requirements do not cause a problem since single crystal ceramics may suffice. However, the technology for making large single crystals suitable for high-current industrial uses is not yet practically available.
It is therefore an object of the present invention to provide a method of producing a superconductive composite wire which is flexible and which need not be in the form of a single crystal. This and other objects of the present invention will be apparent from the following description of the preferred embodiment of the invention, the appended claims, and from the practice of the invention.